so do the hand held programmers(predator) and the plug in chips (edge) work the same way ? i mean are they tuning the same things in the truck?i understand that the hand helds have all the diagnostic benefits and stuff but are they working on the same principle? thanks

Sorta kinda but not really

The Edge plug and play intercepts signals and alters

A ECM downloader extracts your stock tune and downloads a tune that is enhanced,thus giving more options like speed limit defeat tire size calibration,etc.

In a nut shell,that about covers it